Over the past twenty years, various methods for reducing the amount of radiation exposure associated with fluoroscopic examinations have been suggested: some have been implemented; none have found their way into the mainstream of routine clinical practice. Previous methods have failed for a number of reasons: inadequate temporal resolution, cumbersome instrumentation, unacceptable motion artifacts, or a combination thereof. We propose to develop a digital fluoroscopic video image processor (VIP) capable of significantly reducing radiation exposure to patients and to radiology professional staff while maintaining the integrity of the fluoroscopic exam in terms of temporal and contrast resolution, image noise, and digital processing artifacts. The VIP will optimize the use of radiation exposure through two strategies: motion detection and automatic image zoom control. Motion detection will be used to adjust the balance between the incident radiation exposure rate and the level of recursive frame averaging in such a way that the apparent level of fluoroscopic image noise remains constant. An automatic 2:1 digital zoom feature will allow the radiologist to obtain "magnified" views without requiring the dose rate increased associated with the electronic magnification feature of x-ray image intensifiers. During Phase I a prototype of the proposed device will be constructed and tested. During Phase II a low cost, dedicated device will be designed, built and evaluated in a series of clinical studies.